Vaporizer for horizontal vaporizing burner



May 8, 1962 M. D. HUSTON VAPORIZER FOR HORIZONTAL VAPORIZING BURNERFiled May 11, 1959 atnt Patented May 8, 1962 3,033,279 VAPGRIZER FORHORIZONTAL VAPURIZING BURNER Milton D. Huston, Santa Fe, N. Men,assignor to Controls Company of America, Milwaukee, Wis., a corporationof Delaware Filed May 11, 1959, Ser. No. 812,493 Claims. (Cl. 158-91) Myinvention relates to an improvement in burners and, particularly, to animprovement in ignition and vaporizing means for burners.

One purpose is to provide an electric ignition and vaporizing assemblyfor burners which operate on liquid hydrocarbon fuel.

Another purpose is to provide a burner of the type described which willreach the high fire condition of operation with a minimum time lag afterignition.

Another purpose is to provide means for employing stored heat for theinitial vaporization of a substantial volume of liquid hydrocarbon atthe starting stage.

Another purpose is to provide improved means for supplying air forignition and for combustion, to a burner of the type herein described.

Still another object is to provide means for supplying a protectivecurtain or screen of air about a burner pot of the type described whichincreases the efliciency of the burner and minimizes the heat losses.

Another purpose is to provide an improved ignition and vaporizingassembly for such burners which is eflicient in operation and easilyremoved for cleaning and repair when necessary.

Another purpose is to provide such an assembly in combination with aso-called horizontal pot type burner.

Other purposes will appear from time to time in the course of thespecification and claims.

I illustrate the invention more or less diagrammatically in theaccompanying drawings wherein:

FIGURE 1 is a vertical section taken along the axis of the burner;

FIGURE 2 is a partial end elevation of the structure of FIGURE 1, withthe vaporizing assembly shown, and the electric ignition elementremoved; and

FIGURE 3 is a section on the line 33 of FIGURE 1.

Like parts are indicated by like symbols throughout the specificationand drawings.

Referring to the drawings, FIGURE 1 illustrates a horizontal pot typeburner which may be applied to any suitable heater, stove, or furnace,not herein shown. The mounting means for mounting the burner on theheater may be widely varied and do not, of themselves, form part of thepresent invention and, therefore, are not illustrated in detail. It willbe understood, however, that the burner assembly of FIGURE 1 may besuitably positioned on or in relation to a heater or stove in suchfashion that the tlame from the burner is directed into the heater orstove, or to a suitable heat exchange space or assembly.

With reference to the general organization of the burner, it has at oneend an ignition structure, generally indicated at A in FIGURE 1. Thisignition structure carries an ignition device which will later bedescribed in detail and which is located in a space in communicationwith the interior of a vaporizer located generally along the horizontalaxis of the spot, but is itself in a relatively cool zone. It will beunderstood that the fuel to be burned is delivered from a liquid fuelinlet 140 to the interior of the ignition space. The ignition spaceincludes a bottom wall 14a and a dam or weir 14b which forms a puddle ofliquid fuel adjacent the below to be described ignition means. Fueloverflows the dam 14b and flows out upon the bottom 12 of the vaporizingdevice. The liquid fuel is vaporized in the vaporizer, flows outwardlythrough its top opening into the interior of the pot and burns withinthe pot.

As will later appear, ignition is started by the flow of liquid fuelthrough the inlet 140. The details of the control of the liquid fuel donot of themselves form part of the present invention and need not bedescribed herein. It will be understood, however, that means, manual orautomatic, may be employed for initiating a flow of liquid fuel to thespace back of the dam 14b, when heat is desired.

As will later appear, I provide a heating element or resistance 25 whichis normally constantly energized, but which calls for a low output ofenergy. However, it is eifective to store heat in the adjacent parts ofthe burner, including the wick 22 and its tubular support 21. The partsare so proportioned that when liquid fuel begins to flow and forms ashallow puddle back of the weir 14b, the stored heat vaporizes theliquid hydrocarbon, and the resistance 25 ignites it. This ignitionsystem will later be described in greater detail. It will be understood,however, that within a very short space of time the burner can reach thehigh fire stage, and the lag between the instant of ignition and highfire can practically be made as short as 45 seconds or less.

The burner structure of FIGURE 1 includes an outer housing which may becylindrical or generally cylindrical and is indicated at 1. Within itare a plurality of spacers which I indicate at M, in the form of stripswhich may be welded or otherwise secured to the inner surface of thehousing I. Extending from these strips are spacing projections 1b.Within the housing 1 and spaced inwardly therefrom is the wall of theburner proper generally indicated at 2. Positioned between it and theouter housing 1 is an intermediate baflie or shield 8 which is heldcentered in its desired position, for example, by the projections 1b ofthe spacer strips 1a. The strips 1a, after the intermediate bafiie orshield 8 has been slipped into the position in which it is shown inFIGURE 1 may be used to hold the assembly together. Thus, for example,ends of the strip as at 1c may be bent into the holding position inwhich they are shown in FIGURE 1. The sleeve or pot 2 is outwardlyflanged at its open end, as at 2a, in opposition to a correspondinginwardly extending flange If of the outer housing. 3 indicates a burnersupporting ring having a cylindrical flange 3a extending about the outeredge of the sleeve 1. Any suitable gasket 4 may be employed, andsuitable securing members 5, which extend through the flange 2a. Anysuitable means for holding the pot parts together in the position inwhich they are shown in FIGURE 1 may be employed. An outer supportingring 6 is shown as held against endwise movement to the right by bead 1ebut as the details of securing the above described assembly to asuitable heater are not of themselves part of the present invention,they are not herein shown.

The wall of the inner burner sleeve 2 is shown as provided with aplurality of primary air inlet apertures, indicated at 2b. Through theseapertures, shown as arranged in a plurality of circumferential rowsspaced at various distances from the end of the pot, a primary airsupply is admitted. It will be understood that in this type of burner arich mixture is formed by the evaporation of a liquid hydrocarbon bycombustion already going on in the burner. This rich mixture is thenburned by adding to it a suitable supply of secondary air. In thestructure herein illustrated the secondary air is shown as admitted by arow of secondary air inlets 20, arranged near the open end of the potthus formed.

The air supply for the burner may be thought of in connection with flowfrom an initial circumferential plenum chamber X to which air may beadmitted, through an air inlet 7 from a motor driven fan or otherwise.This plenum chamber X extends about a generally cylindrical baffle 16which is provided with one or more relatively small apertures 16athrough which flows the supply of air for the ignition stage of theburner. In order to provide air for the body of the burner and for theprimary air inlets 2b and secondary inlets 20 I deliver air about theexterior of the earlier described intermediate battle or shield 8 to asecond circumferential plenum chamber indicated at Y. The second chambersurrounds the exterior of the pot wall 2 and communicates directly withthe secondary air inlets 2c. The air supply for the primary air inlets2b flows in an opposite direction in the space between the intermediateshield or baffle 8 and the exterior of the pot wall 2.

Thus, at the high fire stage of combustion, a rich mixture of vaporizedhydrocarbon and primary air flows past the secondary air inlets 2c, andcombustion takes place at or beyond the secondary air inlets, the flamepassing through the central aperture of a suitable flame ring 9 suitablymounted on the supporting ring 3. I may find it advantageous to directan impinging movement of air toward the secondary air inlets 2c. Iillustrate, for example, a deflecting ring 10 with a directing flange10a in line with supplemental air inlets 2d in the pot side wall orinner sleeve 2.

The pot structure at the opposite end, at the left of FIGURE 1, iscompleted by a combined end plate and evaporator assembly. The end plateis illustrated at 11 and is shown as having secured to it an evaporatorelement or trough 12 shown in cross-section in FIGURE 3. Its end isclosed as at 12a, but it has an upward opening surrounded by anintermediate Wall 1217 and side walls 120 which extend back from thewall 12b to the rear or closure plate 11. It will be noted that theclearance between the pot and the edges of the side walls 120 increasestoward the rear or left end of the pot. The evaporator assembly definesa chamber in part formed by an outward extension 14 from the back plate11. This extension 14 is shown as having a bottom wall 14a with alimiting ledge 14b which forms a dam for liquid fuel admitted throughthe aperture 14s by any suitable fuel delivery duct, the end of which isshown at 14d. The top wall of the member 14 is shown as provided withforwardly inclined air inlets 14a which deliver air downwardly andforwardly toward a subsequently described igniter. One or moreadditional air inlets may be provided, as at 14g, whereby air passesthrough the rear or back plate 11 and downwardly and forwardly into thevaporizing chamber through the opening surrounded by walls 12b and 12c.The extension 14 of the back plate 11 is provided with an open-ended,upwardly inclined, tubular portion 15 formed to receive the ignitionunit below described. The evaporator unit is also surrounded by a shield16, with one or more air inlet apertures 16a, and the rear or left endof the outer sleeve is closed by the previously mentioned end cap 1a.having a tubular portion 18 surrounding and spaced from the tubularextension 15 of the evaporator assembly or rear plate 11. Any suitablemeans may be provided for securing the back plate. I illustrate, forexample, a clamping ring 19 which is secured to the back plate, forexample, by suitable bolts 20, and which grips a suitable bottom flange22 of the inner sleeve or pot side wall 2. Thus the back plate 11 may bebodily removed from the pot, once the igniter and outer end cap 101 isremoved. The removable assembly thus includes the back plate 11, thebelow described ignition element, and the entire vaporizing chamber. Aswill later appear, the ignition element or assembly is alsoindependently removable from the vaporizing assembly after the end cap1d and before the vaporizing assembly are removed from the burner. Theparts are so proportioned that the wall 12b of the vaporizing assemblymay be withdrawn through the ring 19. The ring 19, in turn, ismaintained in position, when the assembly is removed, for example, by asuitable bead 2g. The bolts 20 may be permanently secured to the ring 19and any suitable nuts 20a employed, which are exteriorly accessible,once the closure 1d has been removed. It will be understood that thefuel supply duct 14d may be connected to any suitable source of liquidfuel supply, not herein shown. It is preferable to form or arrange theduct 14d with some measure of flexibility, to permit the vaporizingassembly to be readily removed from the burner.

In order to ignite the burner I provide a unit which includes thegenerally cylindrical sleeve 21, at the bottom of which is any suitablewick, generally indicated at 22. The details of the ignition unit do notof themselves form part of the present invention. It is advantageous,however, that some means be provided for igniting the liquid fuel supplyto the burner, either electrically or manually.

As an illustration of a practical ignition member I may employ a pair ofspaced, electrically conductive pieces 23 and 24 connected to anysuitable source of electric power. These conduct electrical energy toany suitable resist ance heating element, which may be in the form of acoil 25. The poles 23 and 24 may be supported by any suitable insulatingmembers, such as 26, 27. The wick element 22 may, for example, be in theform of a spirally wound, stainless steel strip which provides adischarge space between the convolutions of the spiral. Air may besupplied to the interior of the housing or tube 21, for example througha suitable air inlet or inlets 21a. The tube 21 has secured to it acircumferential shield 28 which is shown as fitting loosely about theend edge of the tubular portion 13 of the end cap 1d. Thus air may flowthrough the space provided; or air may be otherwise admitted through theshield 28.

I find it advantageous to provide a vaporizing assembly which can bebodily and unitarily removed from the burner, without removing theburner from the heater to which it is attached or without removing theconstant level fuel supply gage and from which, in turn, the ignitionelement may also be separately removed.

It will be realized that whereas I have described and illustrated apractical and operative device, nevertheless, many changes may be madein size, shape, number and disposition of parts without departing fromthe spirit of my invention. I therefore wish my description and drawingsto be taken as in a broad sense illustrative or diagrammatic rather thanas limiting me to my specific disclosure herein.

The use and operation of the invention are as follows:

I illustrate a known type of burner in which a liquid fuel is vaporizedand burned. As above mentioned, I illustrate my invention as applied toa burner in which a rich mixture is first formed by combining a primaryor limited air supply with vaporized hydrocarbon, the rich mixture beingconverted to a final and thinner combustible mixture by the addition ofa so-called secondary air supply.

Referring for example to FIGURE 1, which shows the air supply as goingfirst to the circumferential plenum chamber X, that part of the airsupply necessary for the initiation of combustion flows through one ormore apertures 16a in the ring or baffle 16. Part of this air flowsthrough the aperture 21a or its equivalent into the preliminary orinitial combustion space about the normally hot ignition coil or wire25. More air flows to the space about the exterior of the wick 22, forexample through the inlets Me. Additional air may be directed by inlets14g through the wall 11 and downwardly into the vaporizer structure 12.Additional air is also supplied through the second circumferentialplenum chamber Y directly to the secondary air inlets 2c and also,between the burner wall 2 and the baflle 8, to the primary air inlets2b.

Assume that the burner control is calling for heat. A suitable motordriven fan (if a forced draft is desired) begins to operate through theclosing of a suitable motor switch, and air is delivered therefrom tothe plenum chamber X and thence through the various passages and inletsabove mentioned, both to the ignition space and to the interior of theburner proper.

A primary purpose of the present structure and method is to produce highfire conditions with as little delay as possible. As a matter ofpractical example, I find it possible to reach the high fire stage in aslittle as 45 seconds after ignition. This quick operation and rapidactuation is obtained substantially as follows.

With a relatively small input of electric energy the resistance 25 orits equivalent has been giving out heat. It may be left permanently onif desired. Heat is stored in the wick 22 and in the lower end of thewick support or tubular passage 21. Some heat is also stored in adjacentparts of the burner, for example, in the relatively thick side andbottom portions 14 and 14a of the ignition part of the device.

Assume that when heat is called for, a liquid hydrocarbon begins to flowfrom any suitable source through the inlet 14c. This liquid fuel isdammed by the dam or weir 14b and the result is the quick formation of arelatively shallow pool of liquid fuel. It may for example be as shallowas one-sixteenth of an inch in structure of the type shown in FIGURE 1in which the burner pot has a diameter of seven inches. I employ theheat stored in the wick and its support and adjacent parts of the burnerto vaporize the puddle of liquid hydrocarbon which thus forms. It isimportant that the parts be so proportioned that this stored heat willbe drawn otf at an optimum rate. If the puddle were too deep it would bedrawn off quickly in a flash of flame. If it is not deep enough thevaporization of the liquid hydrocarbon proceeds at too slow a rate. Iconsider it best to so proportion the parts that, upon the initiation offlow of the liquid hydrocarbon there is an almost immediate vaporizationof a greater gaseous volume than will be burned about the wick or in thevaporizer. With a proper relation between the stored heat and theinitially dammed volume of liquid hydrocarbon, the excess vaporizedhydrocarbon flows throughout the interior of the vaporizer 12 and out toits upper opening into the interior of the pot which surrounds it. Ineffect and within a span of time as short as forty-five seconds I findthat the pot proper is filled with vaporized hydrocarbon, and that thishydrocarbon is mixing with primary air flowing to the inlets 2b. Thisprimary mixture is further flowing past and being mixed with airadmitted through the secondary air inlets 2a. In other words, withinsubstantially less than a minute after the ignition the burner may bemade to burn at high fire conditions.

It should be kept in mind that in my burner and method, what controlsignition is notthe closing of an electric circuit to heat an ignitionmember. On the contrary, the ignition member may be constantly heated.What controls my ignition is timing of the delivery of a liquidhydrocarbon to an ignition zone where it is vaporized by stored heat andis actually ignited by a hot wire or its equivalent.

I make provision for propagating the ignition throughout the burnerimmediately following the initial ignition stage. The air supply through142 provides for a combustible mixture exterior to the wick 22.Additional air inlets 14g direct a supply of air downwardly into the topof the vaporizer 12 and finally, the volume of liquid hydrocarbonvaporized by this rapidly spreading combustion promptly flows out of thevaporizer and through out the interior of the pot and, receiving itsprimary air through inlets 2b and its secondary air through the inlets2c, burns at the desired high fire stage. The flame then extends throughthe aperture in the flame ring 9 and into the combustion space notshown.

In considering specifically the flow of air during the normal operationof the device, air is first supplied through the inlet 7. Any suitablemeans may be employed for maintaining the desired pressure differential,for example, I may use a motor driven fan or the like.

As indicated generally by X in FIGURE 1 the air is within the left orouter end of the outer housing 1, within the rear closure cap structure,generally indicated as 11, and exterior to the cylindrical sleeve 16.Some of the air flows however through inlets 16a to the space within thesleeve 16, and the rest of the air in the circumferential space orplenum chamber X escapes to the right, referring to the position of theparts of FIGURE 1 and flows about the exterior of the intermediatebaffle or sleeve 8. The air thus reaches a circumferential space aboutthe right hand end of the inner housing 2. referring to the position ofparts as shown in FIGURE 1. This end space is indicated at Y in FIGURE 1and communicates directly with the secondary air inlet 20. Primary airis supplied to the inlets 2b in the wall of the sleeve 2 by the flow ofair inwardly between the sleeve or bafile 8 and the inner wall 2, thisflow being to the left referring to the position of the parts as shownin FIGURE 1. Thus the primary and the secondary art is supplied to theburner proper by air flowing first outwardly along the exterior of thebaflle 8 and then inwardly between the balfle 8 and the wall 2.

Thus there is in effect a screen of flowing air flowing about theexterior of the baffle 8 and another screen of air flowing between theinterior of the bafile 8 and the wall 2. In effect this insulates theouter Wall or housing 1 and much limits the escape of heat from theburner and protects the exterior of the burner assembly from undueheating, destruction of the pigment, etc. Above all, and far moreimportant than any such supplemental advantage, is the fact that thesleeve or baffle 8 serves to conserve reused heat to prevent heat lossfrom the burner and to provide a more eflicient and economical operationof the burner.

It is a characteristic of the burner that a relatively small vaporizermust be used, the structure of 12 and following, and in connection withthe smaller vaporizer the burner must be operated at a highertemperature. The structure above described enables the burner to operateefliciently with a relatively small vaporizer, without difiiculties andwithout exterior overheating. If the bafile 8 were removed theefliciency of the operation would be greatly reduced and a vaporizer ofthe size indicated might actually have substantial difliculty invaporizing the supply of fuel which normally would have to be fed to it.

It should be noted that the vaporizing and ignition assemblies can eachbe bodily and quickly withdrawn from the burner. It should be noted,also, that the electric ignition element, while it is in communicationwith the space of the vaporizer unit, is actually outside of the burner.It is thus possible to remove the ignition element, end cap, andvaporizer or the ignition element alone for inspection and replacementwithout disturbing the remainder of the burner pot.

In addition, the outer housing 1 and 1d is important because it forms apressure chamber about the pot proper to insure a greater pressure abovethe upper end extension 15 of the vaporizer than inside the vaporizer.Thus, noxious vapors and odors, including formaldehyde, that are presentin any burner using liquid hydrocarbon fuel are not allowed to escape toatmosphere between the igniter tube 21 and the extension 15.

I claim:

1. In a horizontal pot-type burner and vaporizer assembly, a pot havinga plurality of air inlets spaced along its axis and about itscircumference and a vaporizer assembly closing one end of the pot andhaving a chambered fuel receiving portion extending within the pot andgenerally along its axis, a fuel inlet connected to the assembly at apoint exterior to the pot to provide a flow of fuel along the bottom ofthe assembly, ignition means in- 7 eluding Wicking positioned in aportion of the assembly exterior to the pot, said Wicking beingpositioned to contact said flow of fuel, and a hot wire adjacent saidwicking to heat it, that portion of the assembly extending Within thepot comprising a confined vaporizing zone which is in communication withthe pot,

2. The structure of claim 1 further characterized by and including meansfor delivering air to the space about said hot wire and wicking.

3. The structure of claim 1 further characterized in that the chamberedfuel receiving portion includes a housing having closed bottom and sidewalls and a defined opening at the top, said defined opening beingremote from the open end of the pot.

4. The structure of claim 3 further characterized by means for directingair downwardly toward said defined opening.

5. The structure of claim 1 further characterized in that said assemblyincludes heat storage means adjacent the fuel inlet.

References (Jited in the file of this patent UNITED STATES PATENTS

